This application is based on Patent Application No. 10-328575 (1998) filed on Nov. 18, 1998 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to an information processing apparatus and a printing control method and more specifically to a calibration performed on a printing apparatus.
2. Description of the Prior Art
A printing apparatus is widely used as a device for outputting image information or the like in an information processing system. As such printing apparatus, the printing apparatus (also referred to as a xe2x80x9cprinterxe2x80x9d bellow) of electrophotographic type which uses a laser beam, forms a visible image by fixing toner to a sheet. Also, the printing apparatus of ink jet type, such as bubble jet type, ejects ink onto the sheet to form a visible image. This printing process or printing mechanism is becoming increasingly complicated as the printer""s level of resolution has increased and color images have come to be produced in recent years.
In such a printer, variations in environment condition and wear of parts of the printer change electric and mechanical states of the printer at time of forming the visible image, which in turn may change the visible image being formed. Typical examples of such changes of the visible image include variations in density or a gray scale of a printed image or variations in a tone of a color image.
To deal with such changes in printed images, correction processing on a xcex3 correction table, i.e., a process called calibration, has been performed conventionally. This calibration is carried out as follows in the information processing system including a host device and the printer.
In a first example where the host device sends print data in the form of a PDL print job to the printer, the host device (also simply referred to as a xe2x80x9chostxe2x80x9d bellow) does not perform the calibration but instead the printer individually performs the calibration. More specifically, a controller of the printer accepts a calibration request from an engine of the printer at a predetermined timing and performs the calibration for updating the correction table according to this request. Then, when it receives the print job, the controller corrects the image data (print job) by using the updated correction table.
In a second example where the host sends print data in the form of a multivalued print job, e.g., a binary print job, to the printer which uses the print data as is for printing, the calibration is done by the host. More specifically, the host causes the printer to print a predetermined patch. Then, measurement for the print result is carried out by a color measuring device and the result of the measurement is inputted to the host to perform the calibration for generating correction data. Thus, the host retains this generated correction data and reflects it on the print data (print job) to correct the print data. Other known methods for generating the correction data include: a method in which the calibration is performed by the printer, correction values or the result of the calibration is printed out, and the correction values are sent to the host so that the correction values can be utilized for the correction of the print data; and a method in which the host quantitatively determines the tendency of quality degradation by measuring the density in advance for each condition, including the number of printed sheets and the number of print colors, and the quantitative tendency is used as the correction data.
In the first example stated above, the controller of the printer performs the calibration upon reception of the request from the engine for every predetermined number of sheets printed. Thus, the calibration is carried out periodically in a print data transmission mode such as one performed in the first example. Therefore, the printing is done based on an appropriate calibration result, causing almost no degradation in print quality, with the result that the actual printed result may almost equal a desired printed result in many cases as shown in FIG. 1A.
In one configuration of the second example where the calibration or the correction based on the calibration is not automatically performed, if the calibration is not executed especially, a change in the printer state may be caused and the actual printed result may differ from the desired printed result as shown in FIG. 1B. For such case, the calibration needs to be performed at an appropriate timing, which in turn makes it necessary to generate correction data for the calibration. However, the configuration where the correction data is measured by the color measuring device and the result of measurement is inputted to the host, or where the calibration information is obtained and printed by the engine of the printer and the printed correction values are entered to the host, has a problem that the processing for making measurements and entering data to the host come to be complicated for the user. Further, because the state of the printer changes continuously, it is desired, strictly speaking, that the correction data be generated each time the printing is performed. This, however, is not only inefficient in terms of input processing on the part of the user but not economical because the output other than those required for the intended purpose of printing is repeated.
In the configuration that the predetermined quantitative tendency of quality degradation is used as the correction data, an operating condition of the printer often cannot be identified at the time when the correction data is determined. This makes it impossible to perform accurate calibration.
An object of the present invention is to provide an information processing apparatus and a printing control method which enable a precise and efficient calibration without requiring an user of a printing apparatus to spend a considerable time performing calibration procedure even in a system where a host device performs correction on print data and sends the corrected print data to the printing apparatus.
In a first aspect of the present invention, there is provided an information processing apparatus which can be connected to a printing apparatus in a way that allows a bidirectional communication, the printing apparatus being adapted to generate calibration information used to correct print data and capable of supplying the calibration information in response to a request for the calibration information, the information processing apparatus comprising:
an obtaining means for, in response to a request for printing, requesting the printing apparatus to send the calibration information and obtaining the calibration information from the printing apparatus;
a generating means for generating a print job in which print data is corrected based on the calibration information obtained by the obtaining means; and
a transfer means for transferring the print job generated by the generating means to the printing apparatus.
In a second aspect of the present invention, there is provided an information processing apparatus which can be connected to a printing apparatus in a way that allows a bidirectional communication, the printing apparatus being adapted to generate calibration information used to correct print data and capable of supplying the calibration information in response to a request for the calibration information, the information processing apparatus comprising:
an obtaining means for, after printing is request, requesting the printing apparatus to send the calibration information, at predetermined intervals and obtaining the calibration information from the printing apparatus;
a generating means for generating a print job in which print data is corrected based on the latest one of the calibration information obtained at predetermined intervals; and
a transfer means for transferring the generated print job to the printing apparatus.
In a third aspect of the present invention, there is provided a printing control method used in an information processing apparatus which can be connected to a printing apparatus in a way that allows a bidirectional communication, the printing apparatus being adapted to generate calibration information used to correct print data and capable of supplying the calibration information in response to a request for the calibration information, the printing control method comprising the steps of:
in response to a request for printing, requesting the printing apparatus to send the calibration information and obtaining the calibration information from the printing apparatus;
generating a print job in which print data is corrected based on the calibration information obtained by the obtaining step; and
transferring the print job generated by the generating step to the printing apparatus.
In a fourth aspect of the present invention, there is provided a printing control method used in an information processing apparatus which can be connected to a printing apparatus in a way that allows a bidirectional communication, the printing apparatus being adapted to generate calibration information used to correct print data and capable of supplying the calibration information in response to a request for the calibration information, the printing control method comprising the steps of:
after printing is request, requesting the printing apparatus to send the calibration information, at predetermined intervals and obtaining the calibration information from the printing apparatus;
generating a print job in which print data is corrected based on the latest one of the calibration information obtained at predetermined intervals; and
transferring the generated print job to the printing apparatus.
In a system in which the information processing apparatus as a host sends a print job to a printing apparatus to control a printing operation of the printing apparatus, in the case that the print data to be transmitted to the printing apparatus is in the form of binary data that is used as is by the printing apparatus, the configuration described above allows the information processing apparatus, when preparing the print job, to require the printing apparatus to send the calibration information to the information processing apparatus and correct the print data based on the calibration information obtained, thus making it possible for the host to automatically perform the correction based on the calibration information at generating the print job.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.